Unit 3- Sensation and Perception

key words and phrases from chapter 3 of the textbook what is psychology? Pastorino and Doyle-portillo

attention

conscious awareness, can be focused on events that are taking place in the environment or inside our minds

sensation

the process through which our sense organs convert environmental energy such as light and sound into neural signals

perception

the process through which we interpret sensory information

psychophysics

the study of how the mind interprets the physical properties of stimuli

absolute threshold

the minimum intensity of a stimulus at which participants can identify its presence 50% of the time

just noticeable difference (jnd)

the minimum change in intensity of a stimulus that participants can detect 50% of the time

weber’s law

a psychological principle that states that for each of our five senses, the amount of change in the stimulus that is necessary to produce a jnd depends on the intensity at which the stimulus is first presented

what is the absolute threshold for vision?

a candle seen from 30 miles away on a clear, dark night

what is the absolute threshold for hearing?

a ticking watch that is 20 ft away in an otherwise quiet room

what is the absolute threshold of smell?

one drop of perfume diffused in a three room apartment

what is the absolute threshold for taste?

one teaspoon of sugar dissolved in two gallons of water

what is the absolute threshold for touch?

the wing of a bumblebee falling on one’s cheek from a distance of one centimeter

subliminal perception

when the intensity of a stimulus is below the participants absolute threshold and the participant is not consciously aware of the stimulus

extrasensory perception (esp)

also known as psi, the purported ability to acquire information about the world without using the known senses

wavelength

a physical property of some energies that corresponds to the distance between wave peaks

amplitude

a physical property of some energies that corresponds to the height of wave peaks

visible spectrum

the spectrum of light that humans can see

hue

the color of light, it corresponds to the lights wavelength

brightness

the intensity of light, it corresponds to the amplitude of the light waves

saturation

the purity of light, light that consists of a single wavelength produces the richest or most saturated color

cornea

the clear, slightly bulging outer surface of the eye that both protects the eye and begins the focusing process

pupil

the hole in the iris through which light enters the eye

lens

the part of the eye that lies behind the pupil and focuses light rays on the retina

accommodation

the process through which the lens is stretched or squeezed to focus light on the retina

retina

the structure at the back of the eye that contains cells that convert light into neural signals

optic nerve

the structure that conveys visual information away from the retina to the brain

blindspot

the point where the optic nerve leaves the retina (the optic disk) where there are no rods or cones

rods

the light sensitive cells of the retina that pick up any type of light energy and convert it to neural signals

cones

the cells of the retina that are sensitive to specific colors of light and send information to the brain concerning the colors we are seeing

photopigments

light sensitive chemicals that create electrical charges when they come into contact with light

dark adaptation

the process through which our eyes adjust to dark conditions after having been exposed to bright light

light adaptation

the process through which out eyes adjust to bright light after having been exposed to darkness

trichromatic theory of color vision

the idea that color vision is made possible by the presence of three different types of cones in the retina that react respectively to red, green, or blue light

color blindness

a condition in which a person cannot perceive one or more colors because of altered cone activity in the retina

according to trichromatic color theory of vision, what colors make yellow?

green and red

according to trichromatic color theory of vision, what colors make cyan?

blue and green

according to trichromatic color theory of vision, what colors make magenta?

red and blue

opponent process theory

the sea that we have dual action cells beyond the level of the retina that signal the brain when we see one of a pair of colors

optic chiasm

the point in the brain where the optic nerve from the left eye meets the optic nerve from the right eye

cycle

a physical characteristic of energy defined as a wave peak and the valley that immediately follows it

frequency

a physical characteristic of energy defined as the number of cycles that occur in a given unit of time

loudness

the psychophysical property of sound that corresponds to the amplitude of a sound wave

decibels

the unit of measurement used to describe the loudness of a sound

pitch

the psychophysical property of sound that corresponds to the frequency of a sound wave

outer ear

the outermost parts of the ear, including the pinna, auditory canal, and surface of the ear drum

middle ear

the part of the ear behind the ear drum and in front of the oval window, including the hammer, anvil, and stirrup

inner ear

the innermost portion of the ear that include the cochlea

cochlea

the curled, fluid filled tube in the inner ear that contains the basilar membrane

basilar membrane

the structure in the cochlear duct that contains the hair cells, which convert sound waves into neural impulses

hair cells

neurons that grow out of the basilar membrane and convert sound waves into neural impulses

auditory nerve

the nerve that carries information from the inner ear to the brain

place theory

a theory that proposes that our brain decodes pitch by noticing which region of the basilar membrane is most active

frequency theory

a theory that proposed that our brain decodes pitch directly from the frequency at which the hair cells of the basilar membrane are firing

volley theory

a theory that proposes that our brain decodes pitch by noticing the frequency at which groups of hair cells on the basilar membrane are firing

duplicity theory

a theory that proposes that a combination of volley and place theory explains how our brain decodes pitch

issues with place theory

place theory doesn’t fare so well in experiments with timbres which are the majority of sounds that we hear

issues with frequency theory

hair cells can only fire at a max rate of 1,000 action potentials per second but we can hear sounds 20-20,000 hz so 1,001-20,000 are unexplained by this theory

issues with volley theory

if volley theory is accurate, why did the tests done to prove place theory (on pure tones) work? the creator of that theory proved that different pitches excite different areas of the basilar membrane

issues with duplicity theory

the most believed theory nowadays, we don’t understand how they work together yet though

gustation

the sense of taste

papillae

bumps on the tongue that many people mistake for taste buds

taste buds

the sense organs for taste that are found between the papillae on the tongue

olfaction

the sense of smell

olfactory epithelium

a special piece of skin at the top of the nasal cavity that contains the olfactory receptors

lock and key theory

a theory that proposes that olfactory receptors are excited by odor molecules in a way that is similar to the way in which neurotransmitters excite receptor sites

pheromones

airborne chemicals that are released from glands and detected by the vomeronasal organs in some animals and perhaps humans

dermis

the inner layer of the skin

epidermis

the outer layer of the skin

gate control theory of pain

a theory of pain that proposes that tiny neural networks in the spinal cord block pain signals from a particular part of the body when they receive additional neural signals from intense tactile stimulation being applied to the same part of the body

kinesthesis

the ability to sense the position of our body parts in relation to one another and in relation to space

vestibular space

the sense of balance

top down perceptual processing

perception that is guided by prior knowledge or expectations

bottom up perceptual processing

perception that is not guided by prior knowledge or expectations

binocular depth cues

depth cues that utilize information from both eyes

retinal disparity

a binocular depth cue that uses the difference in the images projected on the right and left retinas to inform the brain about the distance of a stimulus

monocular depth cues

depth cues that require information from only one eye

gestalt approach

a psychological school of thought originating in Germany that proposed that the whole of a perception must be understood rather than trying to deconstruct perception into its parts

figure ground

a gestalt principle of perception that states that when we perceive a stimulus, we visually pull the figure part of the stimulus forward while visually pushing backward the background or ground, part of the stimulus

closure

a gestalt principle of perception that states that when we look at a stimulus, we tend to see it as a closed shape rather than lines

proximity

a gestalt principle of perception that states that we tend to group close objects together during perception

similarity

a gestalt principle of perception that states that we tend to group like objects together during perception

good continuation

a gestalt principle of perception that states that we have a preference for perceiving stimuli that seem to follow one another as part of a continuing pattern

feature detection theory

a theory of perception that proposes that we have specialized cells in the visual cortex, feature detectors, that fire only when they receive input that indicates we are looking at a particular shape, color, angle, or other visual feature

path of auditory signals

sound waves vibrate the eardrum which begins transmitting these sounds (through vibrations) to the bones in the ear which further pass on the vibrations/sounds to the fluid in the cochlea which vibrates the hair cells in the cochlea which translates the movement into an action potential to be perceived by the brain

where are most of the touch receptors?

dermis

perceptual errors

occur for a variety of reasons, often due to misapplied expectations that lead is to think we have seen or heard something we haven’t